Structural studies of a dinuclear (Cu, Gd) and two trinuclear (Cu2, Ln) complexes (Ln=Ce, Er). Magnetic properties of two original (Cu, Gd) complexes
Abstract
With the aim of increasing the number of structurally characterized dimetallic (CuII, LnIII) complexes, we have obtained a strictly dinuclear (CuII, GdIII) complex 1 in which, according to structural data, the two metal ions are triply bridged. Then, we have investigated the capability of Cusalen precursors for complexing lanthanide ions. Structural and magnetochemical studies show that dinuclear entities with a CuO2Ln bridging network can only be isolated with the heavier lanthanide ions such as gadolinium or erbium (complexes 2, 3 and 4) while trinuclear (CuO2LnO2Cu) complexes are obtained in the case of lighter LnIII ions, such as cerium (complex 5) for example. Ferromagnetic interactions with J values of 4.2 and 3.5 cm-1 characterize complexes 1 and 2, respectively.